Oil pump system for vehicle

ABSTRACT

The present disclosure provides an oil pump system for a vehicle to control an oil flow or a flow rate of oil according to characteristics of an oil flow rate consumed for each component. The oil pump system includes: a mechanical oil pump, an electrical oil pump. In particular, the mechanical oil pump supplies oil to a lubrication component, and the electrical oil pump supplies oil to a cooling component or a control component. The mechanical oil pump and the electrical oil pump are independently operated.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Korean PatentApplication No. 10-2015-0141744, filed on Oct. 8, 2015, which isincorporated herein in its entirety by reference.

FIELD

The present disclosure relates to an oil pump system for a vehicle.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Recently, as part of preparation for depletion of fossil fuel andenvironmental pollution, eco-friendly vehicles such as a hybrid vehicleusing both an engine using fossil fuel and an electric motor operated byelectricity, as driving sources, have been developed and come onto themarket.

An oil pump is installed in a transmission of a hybrid vehicle andconfigured to supply oil to lubricate a lubrication element (e.g., anelement to be lubricated, such as bearing, bush, gear, etc.), cool acooled element (e.g., an element to be cooled, such as an electricmotor, an engine, or a supplemental cooling device for cooling themotor, engine etc.), and form control pressure for a control element(e.g., a clutch, a brake, etc.).

Meanwhile, flow rate characteristics of oil consumed for each elementvary depending on operational conditions of a vehicle, or the like. Forexample, a supply flow rate of oil desired for lubricating a lubricationelement may be increased in proportion to a vehicle speed, and a supplyflow rate of oil desired for cooling a cooled element may be increasedwhen torque of an electric motor is high under hillclimbing/acceleration conditions of a vehicle. A supply flow rate of oildesired for forming control pressure of a control element may besignificantly increased when a speed is changed.

In the oil pump system, some hybrid vehicles use a mechanical oil pumpand an electrical oil pump connected in parallel. Here, the mechanicaloil pump is configured to supply oil to a lubrication element, a cooledelement, and a control element, and when a supply flow rate of oil bythe mechanical oil pump is insufficient such as in an idle state of thevehicle or a low speed section, the electrical oil pump serves toadjunctively supply oil.

However, in the related art oil pump system, since the electrical oilpump adjunctively operates and the mechanical oil pump operates as amain oil supplier, the mechanical oil pump needs an increased pumpcapacity and thus its size may be increased.

Also, since the mechanical oil pump is configured to be directlyconnected to a driving source (e.g., an engine or an electric motor) androtated, a supply flow rate of oil may be increased as revolution perminute (RPM) of the driving source is increased. We have discovered thatwhen a supply flow rate of oil is increased and higher than a flow ratedesired for a transmission according to an increase in a vehicle speed,power of the driving source may be wasted and the fuel efficiency of thevehicle decreases.

In the related art, an oil pump system employing only an electrical oilpump alone, without a mechanical oil pump, has been developed.

In the oil pump system employing only the electrical oil pump alone, theelectrical oil pump may be controlled to appropriately cope with asupply flow rate of oil desired for a transmission, reducing a waste ofoil, and since a mechanical oil pump is omitted, fuel efficiency may beenhanced.

We have discovered, however, that since oil should be constantlysupplied to a lubrication element, significant energy loss occurs whenelectric energy is converted into mechanical energy in the electricaloil pump, and in addition, when the electrical oil pump is operatedunder an extremely low temperature (e.g., −35° C.), oil itself acts as alarge load, an undesired large motor for driving the electrical oil pumpis requireded.

SUMMARY

The present disclosure provides an oil pump system for a vehicle, inwhich a mechanical oil pump is configured to supply oil toward alubrication element and an electrical oil pump is configured to supplyoil toward a cooled element and a control element, and the mechanicaloil pump and the electrical oil pump are independently driven tooptimally control an oil flow or a flow rate of oil according tocharacteristics of an oil flow rate desired for each of the elements.

According to an exemplary form of the present disclosure, an oil pumpsystem for a vehicle includes: a mechanical oil pump configured tosupply oil to a lubrication element; and an electrical oil pumpconfigured to supply oil to at least any one of a cooled element and acontrol element, wherein the mechanical oil pump and the electrical oilpump are independently operated.

A first oil flow channel for supplying oil toward the lubricationelement may be connected to the mechanical oil pump.

The mechanical oil pump may be connected to a driving source of avehicle so as to be operated.

A second oil flow channel for supplying oil toward the control elementmay be connected to the electrical oil pump.

A third oil flow channel for supplying oil toward the cooled element maybe connected to one side of the second oil flow channel.

A regulator valve may be installed in a portion where the second oilflow channel and the third oil flow channel are connected.

According to another exemplary form of the present disclosure, an oilpump system for a vehicle includes: an oil pan configured to store oil;a mechanical oil pump configured to supply oil of the oil pan only to alubrication element; and an electrical oil pump configured to supply oilof the oil pan to at least any one of a cooled element and a controlelement, wherein the mechanical oil pump and the electrical oil pump areindependently connected to the oil pan.

A first intake line may be connected to an inlet of the mechanical oilpump, the first intake line may be connected to the oil pan, and a firstoil line supplying oil to the lubrication element may be connected to anoutlet of the mechanical oil pump.

A second intake line may be connected to an inlet of the electrical oilpump, the second intake line may be connected to the oil pan, and asecond oil line supplying oil to the control element may be connected toan outlet of the electrical oil pump.

The first intake line and the second intake line may be independentlyconnected to the oil pan.

A third oil flow channel supplying oil toward the cooled element may beconnected to one side of the second oil flow channel, and a regulatorvalve may be installed in a portion where the second oil flow channeland the third oil flow channel are connected.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a view illustrating an oil pump system for a vehicle;

FIG. 2 is a diagram illustrating an oil pump system for a vehicle;

FIG. 3 is a diagram illustrating a transmission of a hybrid vehicle towhich an oil pump system for a vehicle is applicable; and

FIG. 4 is a graph illustrating a relationship between an oil flow rateof an electric oil pump of an oil pump system for a vehicle and avehicle speed.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

For reference, dimensions of elements or thicknesses of linesillustrated in the drawings referred to describe the present disclosuremay be exaggerated for the convenience of understanding. Also, the termsused henceforth have been defined in consideration of the functions ofthe present disclosure, and may be altered according to the intent of auser or operator, or conventional practice. Therefore, the terms shouldbe defined on the basis of the entire content of this specification.

Referring to FIGS. 1 and 2, an oil pump system for a vehicle accordingto an exemplary form of the present disclosure includes: an oil pan 15storing oil, a mechanical oil pump 11 supplying oil to a lubricationelement 21, and an electrical oil pump 12 configured to supply oil to atleast one of a control element 22 or a cooled element 23.

The mechanical oil pump 11 is configured to pump oil of the oil pan 15and supply the oil toward the lubrication element 21. Here, thelubrication element 21 refers to a component making a motion relative toa peripheral component and thus generating frictional abrasion and heat,such as a bearing, a bush, and a gear.

As illustrated in FIG. 1, the mechanical oil pump 11 is connected to adriving source 1 such as an engine or an electric motor of a vehicle,and thus the mechanical oil pump 11 operates as the driving source 1 ofthe vehicle is driven,. The mechanical oil pump 11 may increase a supplyflow rate of oil in proportion to a vehicle speed. In other words, thesupply flow rate of oil increases according to the increase of thevehicle speed.

In particular, since the mechanical oil pump 11 is configured to supplyoil only toward the lubrication element 21 (e.g., a bush, a bearing,gears), oil may be supplied according to a desired flow rate of thelubrication element 21, and thus, a waste of oil may be reduced even athigh RPM of the driving source 1 (e.g., an engine or a motor), and thusthe fuel efficiency of the vehicle and the efficiency of the lubricationon the lubrication element 21 are improved.

A first oil flow channel 31 for supplying oil toward the lubricationelement 21 (e.g., a bush, a bearing, gears) may be connected to themechanical oil pump 11, and a relief valve 31 a may be installed on oneside of the first oil flow channel 31.

A first intake line 41 may be connected to an inlet of the mechanicaloil pump 11 and connected to the oil pan 15, and the first oil flowchannel 31 is connected to an outlet of the mechanical oil pump 11.Thus, the mechanical oil pump 11 may intake oil of the oil pan 15through the first intake line 41 and subsequently supply oil toward thelubrication element 21 through the first oil flow channel 31.

The electronic oil pump 12 is configured to pump oil from the oil pan 15and supply the oil to the control element 22 and/or the cooled element23. Here, the control element 22 may be a clutch or a brake operated byoil which is supplied or discharged thereto, and the cooled element 23may be a driving source of a hybrid vehicle or an electric vehicle (e.g.a motor or an engine), an additional cooling device for cooling anelectric motor or engine, or the like.

As illustrated in FIGS. 1 and 2, a motor 16 is connected to theelectrical oil pump 12, and the electrical oil pump 12 is operated bythe motor 16. A controller (not shown) calculates a supply flow rate ofoil desired for forming control pressure of the control element 22and/or cooling the cooled element 23 and subsequently controls the motor16 according to the flow rate desired for the control element 22 and/orthe cooled element 23, whereby the electrical oil pump 12 may supply anappropriate amount of oil corresponding to the flow rate desired for thecontrol element 22 and/or the cooled element 23.

For example, the electrical oil pump 12 may be independently driven bythe motor 16 to control a supply flow rate of oil, regardless of thedriving source 1 of the vehicle, and thus, formation of control pressureof the control element 22 and/or cooling of the cooled element 23 may bestably and independently performed regardless of a vehicle speed.

A second oil flow channel 32 for supplying oil toward the controlelement 22 is connected to the electrical oil pump 12, and a third oilflow channel 33 for supplying oil toward the cooled element 23 isconnected to one side of the second oil flow channel 32.

In particular, a regulator valve 34 for forming control pressure of thecontrol element 22 may be installed in a portion where the second oilflow channel 32 and the third oil flow channel 33 are connected. Whenoil is supplied to the control element 22 through the second oil flowchannel 32 according to an operation of the electrical oil pump 12,control pressure of the control element 22 may be formed by theregulator valve 34, and after the control pressure is formed, oil mayflow to the third oil flow channel 33 so as to be supplied toward thecooled element 23. A relief valve 33 a may be installed on one side ofthe third oil flow channel 33.

As described above, the electrical oil pump 12 may control a supply flowrate or a flow of oil by controlling the motor 16 or the regulator valve34 regardless of a vehicle speed, and thus, the electrical oil pump 12may appropriately supply oil according to a desired flow rate of thecontrol element 22 and/or the cooled element 23.

A second intake line 42 is connected to an inlet of the electrical oilpump 12 and connected to the oil pan 15, and the second oil flow channel32 is connected to an outlet of the electrical oil pump 12.

In particular, since the mechanical oil pump 11 and the electrical oilpump 12 are independently connected to the oil pan 15 through the firstintake line 41 and the second intake line 42, respectively, they mayindependently operate more smoothly.

FIG. 3 is a view illustrating a transmission of a hybrid vehicle towhich an oil pump system for a vehicle according to an exemplary form ofthe present disclosure is applicable.

The transmission for a hybrid vehicle illustrated in FIG. 3 has an inputshaft 2 connected to an engine 1, a planetary gear set 3 installed inthe input shaft 2, a first electric motor 4 selectively connected to theplanetary gear set 3, a second electric motor 5 installed in a middleshaft 6 parallel to the input shaft 2, an overdrive brake 7 connected tothe first electric motor 4, and a one-way clutch 8 connected to theplanetary gear set 3.

As illustrated in FIG. 3, the mechanical oil pump 11 of an oil pumpsystem for a vehicle is connected to the engine 1 through a gear or apulley, and the electrical oil pump 12 may be disposed to be adjacent tothe mechanical oil pump 11.

The oil pump system for a vehicle may be applied to a transmission of ahybrid vehicle illustrated in FIG. 3 to supply oil according to a supplyflow rate of oil desired for the lubrication element 21, the controlelement 22, and the cooled element 23.

As a vehicle speed is increased, the lubrication element 21 hasincreased frictional contact or heat, and accordingly, an increased flowrate of oil for lubricating the lubrication element 21 is desired. Here,as illustrated in FIG. 4, the mechanical oil pump 11 may increase asupply flow rate of oil supplied to the lubrication element 21 inproportion to the vehicle speed through a structure connected to theengine 1 of the vehicle (please refer to A of FIG. 4).

The cooled element 23, such as the electric motor 4 or 5 as an auxiliarydriving source, of the vehicle is rapidly increased in temperature underhill climbing conditions in which a vehicle speed is low and high torqueis desired. Under this condition, the cooled element 23 is desired to becooled, regardless of vehicle speed. When the cooled element 23 isdesired to be cooled, an appropriate amount of oil may be supplied bythe electrical oil pump 12 toward the cooled element 23 (please refer toB1 of FIG. 4).

Also, when the overdrive brake 7 is coupled to drive a vehicle at a highspeed and thus to enhance fuel efficiency, the electrical oil pump 12supplies an appropriate amount of oil toward the control element 22(please refer to B2 and B3 of FIG. 4)

In a case where the electric motor 4 or 5 is desired to be cooled undercondition that the overdrive brake 7 is coupled, that is, in a casewhere not only formation of control pressure for the control element 22but also cooling of the cooled element 23 are simultaneously desired,the electrical oil pump 12 supplies an appropriate amount of oil towardthe control element 22 and the cooled element 23 (please refer to B4 ofFIG. 4).

As described above, since the electrical oil pump 12 and the mechanicaloil pump 11 are operated independently each other, an oil flow or a flowrate of oil may be controlled according to conditions desired for eachelement so that fuel efficiency of the vehicle is enhanced. Also, sincepumping capacity of each of the oil pumps 11 and 12 is reduced, a size,weight, and manufacturing cost may be reduced. In addition, due to thereduction in capacity of each of the oil pumps 11 and 12, a low voltagemay be used through a reduction in maximum torque of the motor 16 of theelectrical oil pump 12 under an extreme low temperature condition, thusincreasing safety of a fail safe.

As described above, according to exemplary forms of the presentdisclosure, since the mechanical oil pump is configured to supply oiltoward the lubrication element, the electrical oil pump is configured tosupply oil toward the cooled element and the control element, and themechanical oil pump and the electrical oil pump are independentlydriven, an oil flow or a flow rate of oil may be properly controlledaccording to characteristics of an oil flow rate desired for eachelement.

Hereinabove, although the present disclosure has been described withreference to exemplary forms and the accompanying drawings, the presentdisclosure is not limited thereto, but may be variously modified andaltered by those skilled in the art to which the present disclosurepertains without departing from the spirit and scope of the presentdisclosure.

What is claimed is:
 1. An oil pump system for a vehicle, the oil pumpsystem comprising: a mechanical oil pump configured to supply oil to alubrication element; and an electrical oil pump configured to supply oilto at least one of a cooled element or a control element, wherein themechanical oil pump and the electrical oil pump are independentlyoperated.
 2. The oil pump system according to claim 1, wherein a firstoil flow channel configured to supply oil toward the lubrication elementis connected to the mechanical oil pump.
 3. The oil pump systemaccording to claim 2, wherein the mechanical oil pump is connected to adriving source of a vehicle so as to be operated.
 4. The oil pump systemaccording to claim 1, wherein a second oil flow channel configured tosupply oil toward the control element is connected to the electrical oilpump.
 5. The oil pump system according to claim 4, wherein a third oilflow channel configured to supply oil toward the cooled element isconnected to one side of the second oil flow channel.
 6. The oil pumpsystem according to claim 5, wherein a regulator valve configured toform control pressure of the control element is installed in a portionwhere the second oil flow channel and the third oil flow channel areconnected.
 7. An oil pump system for a vehicle, the oil pump systemcomprising: an oil pan configured to store oil; a mechanical oil pumpconfigured to supply oil of the oil pan only to a lubrication element;and an electrical oil pump configured to supply oil of the oil pan to atleast one of a cooled element or a control element, wherein themechanical oil pump and the electrical oil pump are independentlyconnected to the oil pan.
 8. The oil pump system according to claim 7,wherein a first intake line is connected to an inlet of the mechanicaloil pump, the first intake line is connected to one side of the oil pan,and a first oil line configured to supply oil to the lubrication elementis connected to an outlet of the mechanical oil pump.
 9. The oil pumpsystem according to claim 8, wherein a second intake line is connectedto an inlet of the electrical oil pump, the second intake line isconnected to the oil pan, and a second oil line configured to supply oilto the control element is connected to an outlet of the electrical oilpump.
 10. The oil pump system according to claim 9, wherein the firstintake line and the second intake line are independently connected tothe oil pan.
 11. The oil pump system according to claim 9, wherein athird oil flow channel configured to supply oil toward the cooledelement is connected to one side of a second oil flow channel, and aregulator valve is installed in a portion where the second oil flowchannel and the third oil flow channel are connected.